Green Building Library
Building Materials
Choosing Green Finish Materials: Flooring
In addition to the usual list of considerations for determining the greenness of finish materials, with flooring, don’t forget energy-efficiency.
- Embodied Energy—Extraction/Manufacturing, Recycling/Disposal
- Recycled Content
- Renewable or plentiful resource
- Toxicity – Indoor Air Quality
- Energy Efficiency
To increase energy efficiency, consider the thermal mass of flooring materials to promote passive heating and cooling within the home. In rooms with south-facing windows, tile, concrete, or brick floors will absorb the sun’s heat during the day and release it during the night. Light-colored paint on the ceiling and walls will reflect light down to the thermal mass, enhancing energy absorption.
Minimize conductive heat loss and gain by installing wool carpet with a thick pad. Cork and linoleum tiles are natural insulators that prevent heat loss in the winter and gain in the summer. Area rugs over bare floors provide seasonal flexibility. They can be used during cold seasons and removed in hot weather.
Does your existing floor really need to be replaced? Wood flooring lends itself to refinishing and cork and linoleum can often be repaired. Reclaimed wood flooring is also an option. Check out reuse and reclaimed materials stores in your area to see what’s available.
Adhesives and finishes for floors should be low-VOC only. Wood, bamboo and biocomposites can be nailed, stapled, floated or glued over many surfaces. Floating laminate floors don’t need to be attached at all. Natural materials will biodegrade safely if they contain minimal contaminants. Cut and prepare materials outdoors to minimize dust and out gassing, then bring them in for installation. Many wood floor products can be purchased prefinished at the factory, minimizing VOC exposure on the job site. Concrete slabs need to be fully cured before installing flooring. Follow individual manufacturer instructions for vapor-emission levels. Letting the concrete double as the finish floor will avoid this problem.
Consider the transportation distance of your materials. Choose domestic products, when possible. What is the extraction and manufacturing process used to produce the material? The high-embodied energy in some flooring materials may be balanced by using a smaller amount of material, or its durability may outweigh other considerations. If you emphasize durability as a strong green feature, be prepared to live with your choice for many, many years. For all products, take the time to check Material Safety Data Sheets (MSDS) provided by the manufacturer or found by searching the Web.
Bamboo
Cut and regrown every 5-10 years, bamboo is a renewable resource. However, there is no FSC certification available for sustainable management practices. Not all bamboo is equal in quality. Some may have been treated with pesticides, fungicides, fireproofing chemicals or have urea-formaldehyde as a binder. Only a few species are appropriate for flooring and some of those are better in dry climates than others. If the flooring is a veneer, look for an FSC-certified wood core. Bamboo may warp in high moisture and humidity – it’s not appropriate for bathrooms. There are few domestic sources of bamboo. Preferred suppliers buy from operations with sustainable management practices.
Biocomposite
These are manufactured from agricultural byproducts. They are annually renewable and made from wheat or sorghum chaff, sugar cane pulp, sunflower hulls, etc. Some are marketed as hard enough for flooring, although their long-term performance is somewhat unknown. Maintenance varies according to the material used. Make sure low-VOC binders and sealers are used.
Carpet
Durable, all-natural wool from domestic sources can be a good choice. Avoid imported wool as it may be treated with pesticides. Other natural fibers are nontoxic, but less durable. Consider the padding as well. Synthetic carpet off gasses and traps and holds dust, dander and chemicals from the outdoors. All carpets can harbor allergens and mold. The Carpet and Rug Institute tests emissions through its Green Label program. Carpet recycling is available for some synthetics.
Concrete
Concrete is a flexible material easily formed into different shapes and finishes, is durable and heat-resistant. It must be sealed and resealed and may crack (this is less likely if fly ash has been added). Concrete has high embodied energy, off gasses and isn’t a renewable resource. As a material for floors, it may contain recycled content (fly ash). Concrete colored by natural and nontoxic synthetic pigments added to wet concrete is lower in toxicity than concrete treated with chemical stains and acid washes. With a finished concrete floor, no other material is required, thus saving resources.
Cork
This material originates from Mediterranean countries—look for FSC certification. Cork is renewable. The bark is stripped every 10 years without damage to the tree. It’s naturally water resistant, antimicrobial, deters pests and is fire-retardant. Cork doesn’t mold or outgas and is both durable and biodegradable at the end of its life.
Linoleum
This material contains linseed oil, pine resin, wood flour, cork and limestone with a natural backing made of jute or hemp. It’s recyclable and biodegradable but the strong odor can be a problem for sensitive individuals. This, however, will taper off over time. Linoleum tolerates minor scratches (self-heals), doesn’t tolerate heat, is durable unless it gets excessively wet and is recyclable. No sealer is required and when severely damaged it may be patched.
Stone – Natural
The cost for stone floors is high, but they may never need to be replaced. If they are removed, they can be returned to the earth. However, as they are made from a finite resource, look for reclaimed or nearby sources. Natural stone is durable but is porous and must be sealed and resealed regularly. It’s possible for granite to contain radon.
Tile – Ceramic, Glass, Porcelain
Fired tile makes a zero-VOC and durable surface. There are many styles to choose from and it can contain recycled content and be recycled. Look for at least 50 percent recycled content and use nontoxic grout and sealer. The grout and sealer must be maintained. Glass tile can contain 100 percent recycled material and be 100 percent recyclable. Also consider purchasing tile from a reuse store.
Wood
Look for local, sustainable sources of wood that are FSC certified and reclaimed from domestic sources. If you use reclaimed wood, make sure it’s free from industrial chemicals and agricultural pesticides. Wood can be treated with natural oils and low-VOC finishes. It is very durable—if necessary, it can be sanded and refinished. Most woods mature over many years and are only very slowly renewable. However wood flooring has less embodied energy than mined material such as stone. Look for FSC certification when purchasing flooring from new wood resources. If using engineered wood, look for FSC certified formaldehyde-free products. Factory staining and finishing diminishes VOC out gassing in the home. Wood can be reused and is biodegradable over the long term.
Here are a few less common flooring choices you may want to look into:
Earthen Floors
Most often made from local clay soils, sand and chopped straw, earthen floors are durable when sealed, usually with an oil mixed with solvent. Because they’re made from local materials and require no manufacturing, earthen floors have very low embodied energy.
Leather
This flooring material creates a soft, cushioned and durable surface. Look for recycled leather from clothing and upholstery scraps. Leather is sealed with natural oils and waxes, but isn’t suitable for damp areas.
Rubber
Rubber floors can be made from recycled tire chips which are petroleum based. Their use may prevent landfilling, but safety may be an issue. The material has been exposed to toxins and has a distinct odor.
Terrazzo
Comprised of aggregate in cement or resin. Aggregates of recycled glass can be eco-friendly, but beware of others made from toxic materials. Cement has a high-embodied energy, but is extremely durable. For terrazzo with a resin matrix, check the MSDS for toxic elements. Resin products don’t biodegrade safely and effectively.
Check out the Flooring category in the Oikos Product Directory to get started in your search for green flooring options:
